After six years, development on Window Maker has picked up again. Other than mere bug fixes, the two new releases (so far) also include lots of code cleanup and, yes, new features as well. Welcome back!

for GTK2/3 and QT4? Back in in the day (GTK 1 and QT3) it was pretty easy to get programs to match the Window Maker style, but as NeXTSTEP has receded farther into the past, themes have become harder to come by.

There is still GTK2step available in some places, but it hasn't been updated in years. A quick search reveals that there are RPMs available. You apply this theme to your GTK and explicitly define it in ~/.gtkrc-2.0 (make sure it is defined even if you are using some helper program to apply GTK2 themes) and Qt4 will pick up the theme. Nice consistent interface.

Stupidly, there are some minor appearance bugs in that version which I fixed, but could never get gnome-look to update with, and are now lost somewhere; certainly it would not be impossible to re-fix them.

I'm afraid I don't have the time right now to do that myself or port it to gtk3.